Waterproof sheet structure



Dec. 11, 1928. T 1,694,523

J. F. WHITE WATERPROOF SHEET STRUCTURE Filed Aug. 11, 1924 Patented Dec. 11, 1928.

UNITED STATES PATENT OFFICE.

JOHN F. WHITE, OF CHICAGO, ILLINOIS, ASSIGNOR T WHITE IRODUCTS COMPANY,

OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

WATERPROOF SHEET STRUCTURE.

Applicationvfiled August 11, 1924. Serial No. 731,357.

This invention relates to an artificial sheet material, waterproof in nature and adapted, among other uses, to employment as a structural element. In various industries, notably the automobile industry. very large quantities of light sheet material are required for suchuses as partitions, sheathing for structural frames, supports for finishing fabric and the like. In addition to being light in weight, such material should posess a marked vdegree of flexibility and toughness to resist puncture, suflicient stiffness to hold its proper shape, should be ef' fectively waterproof, and should hold cement or glue for the attachment of finishing material or the like. Sometimes it is further desirable that the material be susceptible of a certain amount of embossing to permit its being given a decorative finish. Due to these several requirements, the production of such a material is not an obvious or easy accomplishment, particularly in view of the fact that the great amount of material used necessitates the reduction of cost to the lowest possible point and the sale of the material at averynarrow profit. A slight reduction in cost effects a large aggregate saving because of the large quantities used. Of course, reduction in cost may be attained by the use of cheap materials, but such expedients ordinarily result in sacrifice in some degree of one or more of the characteristics desired in an article of this kind.

The general purpose of the present invention is the provision of a waterproof sheet structure which possesses the desired characteristics in adequate degree, and yetmay be produced at low cost.

-Another object is the provision of a method for the production of the article.

Other and further objects of the invention and advantages of the same will be pointed out hereinafter,indicated in the appended claims, or obvious to one skilled in the art upon an understanding of the present disclosure.

For the purpose of this application I have elected to set forth one particular structure and one particular method of producing the same, but it is to be understood that they are here presented for illustrative purposes only and are not to be accorded any interpretation such as might have the effect of limiting what I claim as my invention,

' illustrative embodiment.

short of its true and most comprehensive scope in the art.

In the drawing forming a part of the speclfication,

Fig. 1 is a showing of component elements entering into the structure of my new sheet material, the same being in the nature of an edge elevation very considerably magnified as to thickness;

Fig. 2 is a schematic illustration, in the nature of a sidev elevation, of apparatus for practicing my improved method, and

Fig. 3 is an illustration in the nature of an edge elevation, very considerably magnified as to thickness, of a sheet embodying the invention.

For illustration of the uses for which my improved sheet structure is designed, examples may be cited in the construction of automobiles, Here it finds place as the interior sheathing or coving for various structural members of frame portions, such as the interior sheathing ofdoors, body frames, stationary top frames, interior Walls for compartments, etc. \Vhile, as a usual thing, such portions are not called upon to carry any substantial stresses, they nevertheless must hold theirform, be able to resist impact and frequently support other materials having no inherent stiffness, such as interior finish fabric. Moreover, they must accomodate themselves to shape, as for example,

the curving of the interior finish in a stationary ZlHlfOllEOllllQ top at the junction of the rear and side Walls or the rear wall and top. \Vith the general nature of the uses and requirements of the materials thus in mind, an uiulcr.-. tanding of the invention may be had most quickly by reference to an I form my improved sheet as a composite structure. The

major portion, which is designated by the' reference character 10, is a slightly compressible, felted, fibrous sheet, such as is employed in the manufacture of high grade asphaltic roofing. This is thoroughly impregnated with an asphaltic material suitably fluxed or thinned, to render it permanently flexible or plastic, in any of several manners well known in the making of inrpregnated felted sheets for roofing and the like. The impregnating material may be lads from Trinidad or other natural asphalt fiuxed with a petroleum distillate residuum having an asphaltic base or with a hydro carbon oil, and applied while heated. It is of advantage that theimpregnating material have a melt point substan tially above maximum atmospheric temperature, and that it have a degree of flexibility. An appropriate impregnating mixture may be made of asphaltic petroleum distillate residuum having a melt point around 200 F., 20% gilsonite and 20% parafiin. This is applied at high temperature and in such fashion as to thoroughly impregnate the absorptive fibrous sheet of felt or the like. While thoroughly impregnated, the felt material is superfically dry, so that it may be rolled or piled without contacting surfaces sticking together, and it may be handled without the impregnating material working out, rubbing off or collecting adherent foreign matter. I will refer to this portion of the structure as the body portion. To each side of its body portion I apply a sheetof fairly tough paper which is free from sizing and preferably free from any pulverulent filling. This application is accomplished by placing the sheets in surface contact and pressing them together under very high pressures, with the application of heat sufficient to flux some of the impregnating material. An arrangement for carrying on the process is illustrated in Fig. 2, in which the reference character A designates a roll of the impregnated felt material, B an upper roll of the surfacing paper, and the character B a lower roll of surfacing paper. These are fed into surface contact by the feeding rollers C and transmitted by rollers D between the heated platens E of a press.

The feeding of the sheet material from the rolls is accomplished intermittently while the press platens are separated. A degree of pressure is placed upon the superimposed sheets which is suflicient to very substantially compress the body portion 10, rendering it more dense and somewhat reducing its thickness. ,This displaces from the, fibres a certain amount of the asphaltic impregnating material and this, by the pressure and the heat from the platens, is squeezed and drawn into the fibre of the surfacing sheets. The latter are designated by the reference character 11. If left in the press sufficiently long, the asphaltic material may be thus drawn and expressed completely through the surfacing sheets, or, by regulation of the time and pressure, the extent of permeation of the facing sheets may be effected to a desired degree. The treatment effectively and permantly combines the surfacing sheets with the body portion throughout their entire contiguous surfaces. lVhen so combined, the composite web is cut into sheets F of the desired length by cutters G.

"The sheets thus produced have very much more stifiness than the original impregnated felt material and the composite sheet is of somewhat less thickness than the original body sheet. The composite sheet has a substantially smooth surface of more or less marbled appearance, depending upon the amount of penetration of the asphaltic material. The composite sheet is waterproof, both internally and superficially, and may be repeatedly wetted with water without disintegrating or swelling. It is very tough and coherent and highly resistant to puncture. It has no warping tendency, and while lending itself to moulding or curving in either direction, it has very pronounced stability, and after being curved will resume its flat form upon being laid out. It does not crease readily, trims smoothly and presents aclean, well-knit edge. It does not bleed or sweat out the impregnating material, nor does it adhere to contactingarticles. Nevertheless, it holds cement or glue quite securely, so that fabrics or decorative material may be mounted upon it. It will take a pyroxylin coating and may be embossed in conjunction with the same. to give a surface finish in imitation of leather or the like. It does not chip at the edges or easily mar on the surface by abrasion.

One very considerable advantage from the standpoint of cost resides in the fact that the paper and the body material are both ordinary articles of commerce, and the formation of the sheet from them requires no further additionof treating material or adhesive, but is carried out entirely by the application of pressure andheat. Thus there 'is no waste, no special fire hazard and no .mvestment in supples of treating materials.

Moreover, it may be carried on directly in conjunction with the manufacture of the impregnated body material. \Vhile I have referred to the body portion as a sheet of felt, it is to be understood that the term comprehends a wide variety of felted or fibrous materials of absorptive and compressible nature, such as those made of wood pulp as well as those made of vegetable or animal fibre.

I claim: 1. A structural board comprising a flexible felt center portion'impregnated with an adhesive waterproofing material, and havin a thinner flexible surfacing sheet of tougi paper secured to each side by the said waterproofing material and partially impregnated andrendered water repellant thereby, the exposed sides of the surfacing sheets being uncoated and the composite board being flexible.

2. A structural board, comprising a flexible dry felt center portion impregnated with an adhesive waterproofing material and flexible surfacing sheets of tough paper compressed into the felt at opposite sides and secured thereto by the waterproofing material, the exposed surfaces of the sheets being uncoated and the composite board being flexible.

3. A structural board comprising a coherent flexible felt center portion impregnated with an adhesive waterproofing material and highly compressed between tough flexible surfacing sheets which are secured to it by the waterproofing material, said surfacing sheets being uncoated on their outer sides, but partly filled with waterproofing material from the felt, so as to form a water repellant surface which will hold cement.

4. A method of forming a flexible structural board comprising subjecting a drysurfaced flexible sheet of felt having an absorbed impregnation of adhesive waterproofing material to high compression between flexible surfacing sheets of dry paper, while applying heat to the outer surfaces of the latter, and compressing the paper into the felt and expressing some of the waterproofing material from the felt into the paper.

5. The method of forming structural board comprising compressing between flexible surfacing sheets of paper a sheet of felt having an impregnation of adhesive waterproofing material and meanwhile applying heat to said sheets, thereby increasing the density of the felt and expressing waterproofing material from the felt into the surfacing sheets, whereby the latter are rendered resistant to water.

6. The method of forming structural board which comprises disposing flexible non-adhesive surfacing sheets upon opposite non-adhesive surfaces of a flexible sheet of felt having an impregnation of adhesive water-repellant material, then compressing the sheets together and applying heat thereto to compact the felt and express water-repellant material therefrom into the surfacing sheets to form a uniting bond and water-resisting filler therefor.

In testimony whereof I have hereunto signed my name.

JOHN F. WHITE. 

